TVS and Switching Protector for Power Supply Surge Protection
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Solution Overview
Problem
Existing power supply protection systems for communications devices are inadequate in managing overvoltage surges, particularly when lightning strikes occur, as they result in uneven protection capabilities between positive and negative electrodes, leading to potential device damage due to high residual voltages.
Innovation Solution
A protection apparatus comprising a one-way TVS and a switching type protector connected in series between power supply ports, with additional clamping type protectors and a decoupler to shunt surge currents and reduce residual voltage, improving protection from negative to positive electrode voltage surges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single-stage protection circuit with MOV is used for low-level differential mode protection, then the protection circuit can discharge lightning current, but the residual voltage at two ends of the protection circuit is high, causing next-stage circuits to be more easily damaged
Solution Approach 1:
The protection circuit is divided into multiple stages: a first-stage protection circuit with MOV for high-level protection, and a second-stage protection circuit with TVS diode for low-level protection. This segmentation allows each stage to handle different voltage levels, with the first stage absorbing initial surge energy and the second stage clamping residual voltage to protect next-stage circuits.
Solution Approach 2:
The TVS diode acts as an intermediary between the MOV and the protected circuit. It receives the surge current from the MOV and clamps the voltage to a safe level before it reaches the next-stage circuits, effectively mediating the transition from high-voltage surge to acceptable voltage levels.
2Reliability
If a multi-stage protection circuit is used for high-level differential mode protection, then the lightning current can be gradually discharged, but the protection capability from negative electrode to positive electrode is insufficient due to high residual voltage
Solution Approach 1:
The multi-stage protection circuit is segmented into a first-stage protection circuit (MOV) and a second-stage protection circuit (TVS diode), where each stage handles different aspects of surge protection. The MOV handles high-level energy discharge while the TVS diode handles voltage clamping, creating a hierarchical protection structure.
Solution Approach 2:
Different protection mechanisms are applied at different stages: the first stage uses MOV with high energy absorption capability for initial surge, while the second stage uses TVS diode with precise voltage clamping capability for residual voltage control. Each stage has optimized local characteristics suited to its specific protection function.
3Ease of operation
If electrolytic capacitor is used in power supply circuit, then the circuit can function normally, but the protection capability becomes uneven when encountering lightning strikes in different polarities
Solution Approach 1:
The TVS diode serves as an intermediary that equalizes protection capability across different polarities. It receives surge currents regardless of polarity direction and clamps the voltage symmetrically, compensating for the polarity sensitivity introduced by the electrolytic capacitor.
Solution Approach 2:
The protection circuit uses asymmetric component arrangement (one-way TVS diode orientation) to achieve symmetric protection效果. The TVS diode is connected with specific polarity orientation but provides bidirectional protection by clamping voltage spikes regardless of their direction, counterbalancing the asymmetric behavior of the electrolytic capacitor.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively reduces residual voltage and enhances protection capabilities, minimizing damage to next-stage circuits and reducing the overall volume of the protection apparatus, while improving long-wave lightning protection.
Implementation Method 1
the one-way TVS clamps a surge voltage at two ends of the one-way TVS to a clamping voltage
Implementation Method 2
the switching type protector and the one-way TVS are conducted, so as to shunt a surge current
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A protection apparatus, an electronic device, and a power supply are disclosed. The protection apparatus (100) includes: a one-way transient voltage suppressor (TVS) (120), where a negative electrode of the one-way TVS is connected to a positive electrode of a power supply, and a positive electrode of the one-way TVS is connected to a negative electrode of the power supply; and a switching type protector (110), where the switching type protector is connected between the one-way TVS and the positive electrode of the power supply or between the one-way TVS and the negative electrode of the power supply. When a power supply port is affected by a surge from the positive electrode to the negative electrode, the switching type protector and the one-way TVS are conducted, so as to shunt a surge current, and the one-way TVS clamps a surge voltage at two ends of the one-way TVS to a clamping voltage. When the power supply port is affected by a surge from the negative electrode to the positive electrode, the switching type protector and the one-way TVS are conducted, so as to shunt the surge current. The protection apparatus can reduce a residual voltage at two ends of the protection apparatus, and improve a protection capability from the negative electrode of the power supply port to the positive electrode of the power supply port.